BACKGROUND: South Africa's HIV mortality is primarily due to pulmonary disease. No evidence exists regarding a correlation between specific chest radiographic patterns and CD4 levels of immunity in HIV-infected children. OBJECTIVES: We aimed to determine the prevalence of specific radiographic features in HIV-infected children initiating antiretroviral therapy (ART) to develop a guideline of expected baseline radiographic appearances, and the radiographic features that predominate at specific levels of immune suppression (defined by CD4 percentage ranges), which would narrow the radiological differential diagnosis. METHOD: Retrospective review of the baseline chest radiographs of 92 consecutive paediatric outpatients initiating ART. RESULTS: Normal radiographs were reported in 54% of patients. Those with radiographic abnormalities had parenchymal disease (34%), mediastinal disease (22%) and pleural disease (1%). Parenchymal disease was predominantly air space (28%), and mediastinal disease was predominantly cardiomegaly (21%); lymphadenopathy was rare (1%). Radiological appearances of TB were seen in 9% of patients. A statistically significant association was shown between immune suppression and air space disease (p=0.049) with a relative risk of 0.46 (95% CI 0.24 - 0.88) for air space disease in immune-suppressed children. This association was independent of age. CONCLUSION: Baseline chest radiographs in paediatric outpatients presenting for initiation of ART are predominantly normal, but also demonstrate a significant number of pathological radiological features - primarily air space disease and cardiomegaly. The only statistically significant association between radiographic features and immune suppression was air space disease, which correlated with a higher level of immunity